METHOD FOR ALKALINE BATCH COOKING OF FIBER MATERIAL

摘要

An alkaline batch process for the production of pulp from wood chips, wherein the preheated chips are subjected to an extended impregnation step outside the digester for at least 60 min, preferably longer, at a temperature not ex-ceeding the impregnation liquor boiling point at atmos-pheric conditions, and a rapid heating and cooking period in the digester of less than about 90 min, preferably shorter, followed by cooling to below reaction tempera-ture. Fresh alkali is added both during impregnation and the heating/cooking period.